Kakashi in the manga is a fascinating figure. He's intelligent, strategic, and has a unique sense of humor. His development throughout the story shows his growth as a person and a ninja.
Sure, Kakashi is present in the Boruto manga. His role might not be as prominent as in the Naruto series, but he still has significant moments and interactions.
The plot could be that Naruto gets a special mission to protect Kakashi's face from a group of rogue ninjas who want to steal Kakashi's identity. Naruto has to use his unique skills to fend off the attackers and keep Kakashi's face safe.
A possible plotline could be that a new enemy targets Kakashi because of his distinct face features, believing there is some hidden power in his appearance. Naruto then has to protect Kakashi. Another plotline could be a magical spell that gets cast on Kakashi's face, changing his expressions uncontrollably, and Naruto tries to find a way to break the spell.
Kakashi is very much alive in the Boruto manga. The manga doesn't include his death. Maybe you got some misinformation or confused it with another character's fate. But for sure, Kakashi is around.
Some fanfictions might introduce new, original villains. For example, a dark sorcerer - type character who wants to use Naruto's unique chakra for his own evil purposes. Kakashi has to face this sorcerer and his minions to keep Naruto out of harm's way.